• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.6
• /
• pp.886-891
• /
• 2010

Importance of climate change and its impact on agriculture and environment have increased with a rise of greenhouse gases (GHGs) concentration in Earth's atmosphere, which caus an increase of temperature in Earth. Greenhouse gas emissions such as carbon dioxide ($CO_2$), methane ($CH_4$) and nitrous oxide ($N_2O$) in the Upland field need to be assessed. GHGs fluxes using chamber systems in two upland fields having different soil textures during pepper cultivation (2005) were monitored under different soil textures at the experimental plots of National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA) located in Suwon city, Korea. $CO_2$ emissions were 12.9 tonne $CO_2\;ha^{-1}$ in clay loam soil and 7.6 tonne $CO_2\;ha^{-1}$ in sandy loam soil. $N_2O$ emissions were 35.7 kg $N_2O\;ha^{-1}$ in clay loam soil and 9.2 kg $N_2O\;ha^{-1}$ in sandy loam soil. $CH_4$ emissions were 0.054 kg $CH_4\;ha^{-1}$ in clay loam soil and 0.013 kg $CH_4\;ha^{-1}$ in sandy loam soil. Total emission of GHGs ($CO_2$, $N_2O$, and $CH_4$) during pepper cultivation was converted by Global Warming Potential (GWP). GWP in clay loam soil was higher with 24.0 tonne $CO_2$-eq. $ha^{-1}$ than that in sandy loam soil (10.5 tonne $CO_2$-eq. $ha^{-1}$), which implied more GHGs were emitted in clay loam soil.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.20 no.4
• /
• pp.277-283
• /
• 2018

The crop growth model has been widely used for climate change impact assessment. Crop growth model require genetic coefficients for simulating growth and yield. In order to determine the genetic coefficients, regional growth monitoring data or yield trial data of crops has been used to calibrate crop growth model. The aim of this study is to verify that yield trial data of corn is appropriate to calibrate genetic coefficients of CERES-MAIZE. Field experiment sites were Suwon, Jinju, Daegu and Changwon. The distance from the weather station to the experimental field were from 1.3km to 27km. Genetic coefficients calibrated by yield trial data showed good performance in silking day. The genetic coefficients associated with silking are determined only by temperature. In CERES-MAIZE model, precipitation or irrigation does not have a significant effect on phenology related genetic coefficients. Although the effective distance of the temperature could vary depending on the terrain, reliable genetic coefficients were obtained in this study even when a weather observation site was within a maximum of 27 km. Therefore, it is possible to estimate the genetic coefficients by yield trial data in study area. However, the yield-related genetic coefficients did not show good results. These results were caused by simulating the water stress without accurate information on irrigation or rainfall. The yield trial reports have not had accurate information on irrigation timing and volume. In order to obtain significant precipitation data, the distance between experimental field and weather station should be closer to that of the temperature measurement. However, the experimental fields in this study was not close enough to the weather station. Therefore, When determining the genetic coefficients of regional corn yield trial data, it may be appropriate to calibrate only genetic coefficients related to phenology.

• Journal of Korea Water Resources Association
• /
• v.55 no.10
• /
• pp.761-774
• /
• 2022

Accurate hydrologic prediction is essential to analyze the effects of drought, flood, and climate change on flow rates, water quality, and ecosystems. Disentangling the uncertainty of the hydrological model is one of the important issues in hydrology and water resources research. Hydrologic data assimilation (DA), a technique that updates the status or parameters of a hydrological model to produce the most likely estimates of the initial conditions of the model, is one of the ways to minimize uncertainty in hydrological simulations and improve predictive accuracy. In this study, the two ensemble-based sequential DA techniques, ensemble Kalman filter, and particle filter are comparatively analyzed for the daily discharge simulation at the Yongdam catchment using airGRdatassim. The results showed that the values of Kling-Gupta efficiency (KGE) were improved from 0.799 in the open loop simulation to 0.826 in the ensemble Kalman filter and to 0.933 in the particle filter. In addition, we analyzed the effects of hyper-parameters related to the data assimilation methods such as precipitation and potential evaporation forcing error parameters and selection of perturbed and updated states. For the case of forcing error conditions, the particle filter was superior to the ensemble in terms of the KGE index. The size of the optimal forcing noise was relatively smaller in the particle filter compared to the ensemble Kalman filter. In addition, with more state variables included in the updating step, performance of data assimilation improved, implicating that adequate selection of updating states can be considered as a hyper-parameter. The simulation experiments in this study implied that DA hyper-parameters needed to be carefully optimized to exploit the potential of DA methods.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.30 no.2
• /
• pp.17-28
• /
• 2022

The application of supplemental activated biochar pellet fertilizers (ABPFs) was evaluated by investigating key factors such as changes of surface paddy water and soil chemical properties and rice growth responses during the growing season. The treatments consisted of control, activated rice hull biochar pellet (ARHBP-40%), and activated palm biochar pellet (APBP-40%) applications. It was shown that the lowest NH₄⁺-N and PO₄^--P concentrations were observed in surface paddy water to the ARHBP-40%, while the NH₄⁺-N concentration in the control was abruptly decreased until 30 days after transplant in the soil. However, the lowest NH₄⁺-N concentration in the blended biochar application was 9.18 mg L^-1 at 1 day of transplant, but its ABPFs application was observed to be less than 1 mg L^-1 at 56 days after transplant. The lowest PO₄^--P concentration in paddy water treated ARHBP-40% ranged from 0.06 mg L^-1 to 0.08 mg L^-1 until 30 days after transplant among the treatments. For the paddy soil, the NH₄⁺-N concentration in the control was abruptly decreased from 177.7 mg kg^-1 to 49.4 mg kg^-1, while NO₃^--N concentration was highest, 13.2 mg kg^-1 in 14 days after transplant. The P₂O₅ concentrations in the soils increased from rice transplants until the harvesting period regardless of the treatments. The highest K₂O concentration was 252.8 mg kg^-1 in the APBP-40% at 84 days after transplant. For the rice growth responses, plant height in the control was relatively high compared to others, but grain yield was not significantly different between the control and ARHBP-40%. The application of ARHBP-40% can minimize nitrogen and phosphorous application rates into the agro-ecosystem.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.51 no.6
• /
• pp.1-11
• /
• 2023

By comparing and analyzing the effects of the 2013 Suncheon Bay International Garden Expo and the 2023 Suncheon Bay International Garden Expo, designated as Korea's first national garden, this study aims to present basic data for the future operation direction and sustainability strategy. First, in both fairs, satisfaction throughout the event was high, 4.0 or higher. In particular, the satisfaction level of the 2023 Suncheon Bay International Garden Expo was higher than that of the 2013 Suncheon Bay International Garden Expo. As the longest international event held since the COVID-19 pandemic, it reflected the citizens' demand for healing and recharging in natural spaces. Second, as a result of comparing the types of perceptions that affected satisfaction, it was found that economic, environmental, and ecological types commonly affected satisfaction at the 2013 and 2023 Suncheon Bay International Garden Expo. The 2013 Suncheon Bay International Garden Expo established the brand value as an "ecological city" by creating a garden in the city center along with an ecological resource called Suncheon Bay. In addition, the 2023 Suncheon Bay International Garden Expo expanded the scope of the garden to the entire city center. It also attempted to create a city where humans and nature coexist by realizing values, such as responding to climate change and carbon neutrality. In other words, one of the ways to secure urban competitiveness is to attract corporate investment and tourists and build a differentiated brand in Suncheon by promoting the 2023 fair based on the potential ecological values of the region after the 2013 Suncheon Bay International Garden Expo. Therefore, if the Suncheon Bay International Garden Expo continues to develop environmental and ecological content and programs in line with changes in society and tries to establish itself in citizens' perception through cooperation with local governments and residents, it will be able to establish its identity and brand power.

• Korean Journal of Environment and Ecology
• /
• v.38 no.3
• /
• pp.246-262
• /
• 2024

The survey conducted from 2018 to 2020 aimed to investigate the changes in fish fauna and community characteristics in the upper reaches of the Seomgang River, Korea. During the survey period, 35 sites were selected, resulting in the collection of 7,817 fish belonging to 12 families and 40 species. The dominant species was Zacco koreanus, with a relative abundance of 34.5%, followed by Z. platypus at 28.7%. Other significant species included Rhynchocypris oxycephalus (10.2%), Pungtungia herzi (5.3%), and Squalidus gracilis majimae (4.3%). Notably, four protected species - Acheilognathus signifer, Gobiobotia brevibarba, and Cottus koreanus, designated as class II endangered wildlife by the Ministry of Environment- were identified. These species predominantly inhabit the middle and lower reaches, except for Gobiobotia brevibarba, which is found in the upper reaches. Nineteen species, accounting for a 47.5% endemism rate, were endemic to Korea. The study also noted the presence of one climate-sensitive species, Cottus koreanus, and two exotic species, Carassius cuvieri and Micropterus salmoides. Community analysis indicated a trend of decreasing dominance and increasing diversity and richness from upstream to downstream, with a distinct division into uppermost reaches, upper reaches, middle and lower reaches, and lakes. The construction of the Hwaseong Dam has had a significant direct and indirect impact on the fish community. The habitat and abundance of endangered species such as R. pseudosericeus, A. signifer, and G. brevibarba decreased dramatically immediately after the dam's construction, transforming the submerged area from lotic to lentic environments. Approximately 20 years later, the habitats have stabilized, leading to an increase in the fish population and a recovery of the previously diminished endangered species. The river health (FAI) was also evaluated, with 27 sites rated as very good (A), seven as good (B), and one as fair (C). However, endangered species such as A. signifer continue to face threats from dam and river construction, while C. Koreanus has experienced a severe population decline due to river works. Additionally, the presence of the ecosystem-disrupting species M. salmoides in Hwaseong Lake raises concerns. To ensure a stable habitat for fish in the upper reaches of the Seomgang River, it is crucial to avoid indiscriminate river construction, urgently implement restoration policies for endangered species such as A. signifer, and develop management strategies to control the spread of invasive species such as bass.

• Journal of Korea Water Resources Association
• /
• v.57 no.8
• /
• pp.533-548
• /
• 2024

Due to climate change with extreme weather events, occurrences of unprecedented heavy rainfall have become more frequent. Since it is difficult to perfectly predict and prevent flood damages, the limitation of traditional prevention-centered approaches has come a issue. The concept of "resilience" has therefore been developed which emphasizes the ability to swiftly recover from damages to previous states or to even better conditions. In this study, we 1) developed a total of 20 domestic flood resilience indicators based on the 4R principles (Redundancy, Robustness, Rapidity, Resourcefulness), 2) conducted applicability evaluations targeting specific disaster-prone areas, and 3) assessed the importance of each indicator through Analytic Hierarchy Process (AHP) analysis with flood-related experts. To confirm the suitability of the developed flood resilience indicators, multicollinearity analysis was performed, and the results indicated that all 20 indicators had tolerance limits above 0.1 and Variance Inflation Factors (VIF) below 10, demonstrating suitability as factors. Furthermore, evaluations of proposed indicators were carried out targeting disaster-prone areas in 2022(21 areas), and AHP analysis was utilized to determine the relative importance of each indicator. The analysis revealed that the importance of each indicator was as follows: Robustness 0.46, Rapidity 0.22, Redundancy 0.17, and Resourcefulness 0.16, with Robustness exhibiting the highest importance. Regarding the sub-indicators that had the greatest influence on each 4R component, river embankment maintenance emerged as the most influential for Robustness, healthcare services for Rapidity, fiscal autonomy of local governments for Resourcefulness, and drainage facilities for Redundancy.

• Journal of Bio-Environment Control
• /
• v.32 no.4
• /
• pp.359-365
• /
• 2023

Native plants are unique genetic resources that have the potential to be used as ornamental, medical, and food resources. Allium koreanum H.J. Choi & B.U. Oh is one of the native plants distributed in the coastal rocky land of Korea, which has high conservation value due to climate change and reduction of its habitat. This study was conducted to investigate the effects of temperature and hydrogen peroxide on the germination of A. koreanum. The seeds were prepared as untreated (control) or those treated with 1% hydrogen peroxide for 90 minutes (H₂O₂), and the treatments were placed in plant growth chambers set at 15, 20, and 25℃. Regardless of the H₂O₂ treatment, the germination percentage at 15℃, which was 42%, was more than two times higher than that at 20℃ and 25℃, which were 18% and 0%, respectively, 23 days after sowing. The number of days to attain 50% of the final germination percentage (T₅₀) was the shortest at 20℃, but the mean daily germination (MDG) was the highest at 15℃. Therefore, 1% of H₂O₂ treatment did not have a significant effect on the germination percentage of A. koreanum, and a temperature of 15℃ was considered to be optimum to increase the germination percentage of A. koreanum. The results of this study can be used as basic research data for the germination of A. koreanum.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.32 no.3
• /
• pp.31-41
• /
• 2024

Food waste compost with high salt content produced by aerobic digestion, but concerns about application of cropland. To address this issue, food waste is being composted by mixing it with livestock manure, which has a lower salt content. Therefore, this study aimed to evaluate the growth characteristics of red pepper and soil chemical properties for continuous application with different amounts of food waste compost with manure (FWC). Treatments were consisted of no fertilizer (NF), inorganic fertilizer (N-N-P₂O₅-K₂O, 19.0-11.2-14.9 kg 10a^-1), and inorganic fertilizer + food waste compost with manure (NPKFWC). FWC treatment was applied at three treatment rates based on soil organic matter content: 900 kg 10a^-1, 1,800 kg 10a^-1, and 2,700 kg 10a^-1 ( referred to a s FWC 1, 2, 3 , respectively). As a r esult of the red pepper yield was about 1.8 times higher in NPKFWC 1 and NPKFWC 2 than that in the NF, but decreased in the NPKFWC 3, 300% of the recommended FWC application rate. Yield decreased in all FWC treatments with continuous application for three year and also decreased about 40% from 3,265 kg 10a^-1 in the first year to 1,948 kg 10a^-1 in the third year. For the soil chemical properties, the content of soil organic matter, available P₂O₅, and exchangeable cations increased in the FWC treatments, and were higher than the NF. Exchangeable sodium in all treatments was increased slightly compared to the soil before used, and no significant salinization was observed in the FWC. This study confirmed that excessive use of FWC not only reduced nutrient use efficiency, but also decreased the red pepper yield. Therefore, it is concluded that optimum usage of FWC is effective for agroecological impacts.